A variety of pipe joints are used to connect the compressed air pipe right now. There is a common problem for the existing pipe joints, after connecting the connection between the pipe and joint is not firm, and may appear the axial displacement. Therefore, the applicant filed an application titled “a kind of compressed air quick pipe joint” (Application No. 200810063105.6, application date: 2008, Jul. 10). The pipe joint includes the joint tube and end cover, they are connected through removable thread. The snap ring holder is set at the end of the joint tube; the inner end of snap ring holder extends to the inside of joint tube, the sealing ring is set when connected with the snap ring holder. The inner ring of the sealing ring protrudes the inner diameter setting of snap ring holder; the outer end face of snap ring holder sets the metal circlip, including the ring body and tine. The tine turns up towards the direction of snap ring holder, and sets the inclined circle at the opening of snap ring holder. The tine is set in the inclined circle. The promotion component is set at the outer end of circlip, and the two ends are connected with the circlip and boss. When using, tighten the end cover, the boss will push the promotion component, which can push the circlip to strut the tine, and the tine can bite the tube to prevent the prolapse. The patent pipe joint is featured with simple structure, convenient implementation and reliable connection.
However, the large compressed air piping system needs the large-diameter and small-diameter conveying pipes. The pipe joint of the above-mentioned patent is applicable for the connection of small pipeline only. When applying the large-diameter pipeline, for its dead load, the above mentioned pipe joint cannot satisfy the requirement for the connection strength.